This invention relates to an injection molding machine.
In general, injection molding machines include an injection mechanism for heating and melting molding material and for injecting the molten material into cavities defined by a pair of dies, and a die clamping mechanism for clamping and opening the dies. These injection molding machines are classified into three types; vertical, horizontal, and vertical-horizontal. In the vertical or horizontal type, both the injection mechanism and the die clamping mechanism are disposed vertically or horizontally. In the vertical-horizontal type, on the other hand, one of those mechanisms is disposed vertically, while the other is disposed horizontally.
A conventional injection molding machine generally uses a pair of dies which are severally attached to a fixed platen on the injection mechanism side and a movable platen on the die clamping mechanism side. The latter or movable die is separated from the former or fixed die by the die opening operation of the die clamping mechanism after completion of injection molding. Then, products are collected from the movable die at the same station as the station for molding, automatically by a suitable product collecting mechanism or manually by an operator. Since the products are collected at the same station as the molding station, the injection molding operation is interrupted during the product collection. Thus, the injection molding operation can be performed only intermittently, so that the injection molding machine cannot be fully operated and hence is poor in productivity. With such prior art construction, moreover, the product collecting mechanism need be moved to a position where it faces the opened movable die, so that the use of the product collecting mechanism will complicate the injection molding machine in construction. Where the products are collected manually by the operator, the operating efficiency or productivity will be reduced, and it will be hard to achieve reduction of labor. Especially in insert molding, the productivity will be further reduced by insert work.
In order to eliminate the drawbacks of the aforementioned prior art injection molding machines, there have recently been proposed injection molding machines in which the product collection and/or insert work are performed at a station separate from the molding station. All these injection molding machines are of a vertical type in which the injection mechanism is so arranged as to be able to slide vertically and can perform die clamping and opening, as well as injection molding. The conventional movable dies on the die clamping mechanism side, two or three in number, are attached to a slider or turntable capable of straight or rotary movement within a horizontal plane. The injection molding machines of this type are superior in productivity to the conventional injection molding machines because of the separate station for product collection and/or insert work. Such injection molding machines, however, generally take account of the insert work, so that the movable dies used therein are disposed below the fixed die. Therefore, it is a hard task to collect the products which are normally dropped down, and the improvement in productivity is not very great. Further, there are required separate driving mechanisms for the injection mechanism and for the slider or turntable, so that the injection molding machines will be increased in size and complicated in construction. In producing threaded products, moreover, one portion of the fixed die or the movable die need be rotated and will be extremely complicated in structure.